Drilling fluid conditioning casing shoe



Dec. 22,1964 K. A. WRIGHT 3,

DRILLING FLUID CONDITIONING CASING SHOE Filed July 14, 1961 2 Sheets-Sheet 1 F|G.l. FIG.2. 13

INVENTOR. KENNETH A.WRIGHT by I I4 4 I 23 44 23 .ATTORNEYS.

Dec. 22, 1964 w T 3,162,246

DRILLING FLUID CONDITIONING CASING SI-IOE Filed July 14, 1961 2 Sheets-Sheet 2 KENNETH A.WRI.GHT

ATTORNEYS.

United States Patent 3,162,246 DRILLING FLUID CONDITIONING CASING SHOE Kenneth A. Wright, Los Angeles, Calif., assignor to B & W Incorporated, Torrance, Calil'l, a corporation of California Filed July 14, 1961, Ser. No. 124,175 Claims. (Cl. 166-173) This invention relates to casing shoes or the like for use on the lower end of a well casing or pipe and in particular is related to a novel form of easing shoe for conditioning the drilling fluid in the well bore as the casing or pipe is lowered into the well bore.

In the drilling and completion of wells, it is common practice to cement a casing in the well bore preparatory to drilling the well deeper or to perforating the casing for permitting production of oil or gas through the perforations. The well bore is commonly drilled by using a drill bit on the lower end of a drill pipe, rotating the drill pipe to rotate the bit and circulating drilling fluid or mud down through the drill pipe out through the drill bit and up through the annular space between the drill pipe and the well bore for removing the cuttings from around the drill bit. When the desired depth of the well has been drilled for setting the casing, the drill pipe and bit is removed from the well bore and the casing is lowered into place. The drilling fluid or mud remains in the well bore du ing the removal of the drill pipe and the running in of the casing.

The commonly used drilling fluids or muds have thixo tropic properties and therefore tend to gel when the fluid or mud is not kept in motion. Thus, the drilling mud tends to gel while the drill pipe is being removed and before the casing is lowered into the well bore. It is a common and objectionable occurrence that the casing will become stuck in the Well bore before being able to lower the casing to the desired depth. One of the factors causing the casing to be stuck is the gelling of the mud in the well bore and the resultant forces resisting the lowering of the casing through the gelled mud. These forces are developed in the annular space between the exterior surface of the casing and the well bore.

Accordingly it is a principal object of this invention to provide a novel casing shoe in which means are provided for agitating the drilling mud in the annular space between the well casing in the well bore as the casing is being run into the well bore.

Another object of this invention is to provide a casing shoe having means on the external lower end thereof for agitating the drilling mud in the well bore during the running in of the casing to minimize the forces resisting the lowering of the casing due to the gelling of the drilling mud.

Another and more specific object of this invention is to provide a casing shoe having a sleeve mounted on the lower end thereof with an outside diameter substantially equal to the outside diameter of the casing shoe, and wherein flexible members are mounted on the sleeve and protrude into the annular space between the sleeve and the well bore to agitate drilling mud in such annular space upon movement of the casing shoe.

Other and more detailed objects and advantages of this invention will appear from the following description and the accompanying drawings.

In the drawings:'

FIGURE 1 is an elevational view of the preferred form of my invention.

FIGURE 2 is a sectional elevational view taken substantially on the line 2--2 of FIGURE 1.

FIGURE 3 is an elevational-view of the embodiment shown in FIGURE 1, and illustrating the device being lowered in a well bore.

FIGURE 4 is a sectional plan view taken substantially on the line 4-4 of FIGURE 3.

FIGURE 5 is an elevational view showing a modified form of the invention with a portion broken away for clarity.

FIGURE 6 is an elevational view showing a second modified form of the invention.

FIGURE 7 is an elevational view showing a third modified form of the invention.

FIGURE 8 is a sectional plan view taken substantially on the line 8-8 of FIGURE 7.

Referring now to the drawings, the casing shoe, generally designated 10, of this invention has a housing 11 with a cylindrical outer surface 12, and an internal thread 13 on its upper end adapted for threaded connection with a well casing or pipe. v

The inside lower end of the shoe may be provided with a conventional check valve assembly, generally designated 14, having a valve housing 40 with fins 41 supporting a ball 42 adapted to seal against a valve seat 43 upon fluid pressure from outside the shoe. The valve housing 49 and valve seat 43 are supported in concrete 44 which is molded in place within the housing 11 and retained therein by means of the irregular internal surface 15 on the lower end of the housing. A valve assembly of this general type is employed in a conventional shoe commonly known as a float shoe which is used for permitting lowering of the easing into the well bore without the casing filling up with drilling mud, but allowing circulation of fluid down through the casing and out through the shoe.

The valve assembly 14 is entirely constructed of relatively drillable material for permitting subsequent drilling through the shoe after the casing has been cemented in place.

The external lower end of the housing 11 has a cylindrical outer surface 16 of slightly smaller diameter than the external surface 12, thereby forming a downward facing shoulder 16a at the juncture of the cylindrical surfaces 12 and 16.

In order to cause turbulence of the drilling mud within the annular space 9 between the well bore 8 and the outer surface 12 of the shoe or the outer surface of the casing 7 as the casing is lowered into the well bore, an assembly 17 is mounted on the lower end of the housing 11 as hereinafter described. The assembly 17 is comprised of a sleeve 18 and a plurality of flexible members 19 secured to the sleeve and protruding into the annular space.

As illustrated in FIGURES 1 through 4, the flexible members 19 may be constructed of a continuous cable or wire 20 threaded through retainer 21 of sleeve 18 and forming a plurality of upwardly projecting loops 22 and downwardly projecting arch-shaped loops 23. The retainer 21 may be forced down against the cable or wire 20 to secure same to the sleeve 18 and locking tabs 24 and 25 on either side of the retainer 21 may force the loops 22 and 23, respectively, outwardly from the sleeve 18. The sleeve 13 has an internal cylindrical surface 26 adapted to slide over the external surface 16 of the housing 11. The upper end of the sleeve 18 abuts the shoulder 16a and may be secured thereto by any convenient means such as welding 27. The lower end of the sleeve 18 may be also welded to the housing 11 on the surface 16 by Weld metal 28.

When the casing shoe It is attached to the lower end of the casing 7 and lowered into the well bore, the downward projecting flexible members 19 forming arches 23 engage the well bore 8 and are bent upwardly as shown in FIGURE 3. As the casing is lowered into the well, the ball 42 moves up to seal against seat 43 and the drilling mud below the check valve assembly 14 is urged past the flexible members 19 into the annular space and the physical properties by the flexible members 19 which pass through the drilling mud forcedupward in the annular space 9. v

Although the preferred embodiment as illustrated in FIGURES 1 through 4, is shown as a float shoe with a valve assembly 14 in the lower end thereof, the shoe could be of any conventional type such as a guide shoe or bull plug sho'e w her'ein the plug '44 is replaced by the conventional apparatus of a guide or bull plugshoe. The modified forms of my invention, hereinafter described, may also be constructed as bull plug, guide or float shoes as desired, for the particular application;

FIGURE 5 is a modified form of my invention wherein the flexible members 1911 are comprised of a plurality of stiiT spring wires bundled together by ferrules 29 and mounted on the sleeve 18a by retainer clip 21a rather than the cable or wire of the preferred embodiment. FIGURE 5 also illustrates the shoe as a guide shoe 10a with a plug 14a having an internal bore 30.

The second modified form of my invention,'illustrated FIGURE 4 illustrates the plan view of the configuration formed but my invention is of the full scope of the appended claims. 7

I claim:

1. In a tool for use on the bottom end of a well casing for conditioning the drilling fluid in the annular space between the well bore and the casing while running the easing into the well bore, the combination of: a cylindrical housing having upper and lower ends, thread means f on the said upper end of the housing for connecting said external cylindrical portion with an external downward facing shoulder at the upper'extremity of such portion, a

in FIGURE 6, employs the use of a plurality of flexible M members 1911 constructed ofasprin wire and havinga pair of fingers 31 and 32 projecting outwardly from the sleeve 18b rather than the cable loops 22and 23 of the preferred embodiment. The fingers 31 and 32 each have a coil 33 and 34, respectively, at their base for permitting adequate fiexure of the fingers. The flexible member 19b is mounted .on the exterior of the sleeve 18b by means of a retainer clip 215 secured to the exterior of the sleeve and adapted to enclose a foot-piece of the flexible member 19b joining the coils 33 and .34.

The third modified form of my invention illustrated in FIGURES 7 and 8 employs a pair of sleeves 18 each bundled together and projecting sleeve mounted on said cylindrical portion, a plurality of flexible means mounted on said'sleeve and adapted to profor engaging and abrading the well bore wall,iand atleast part of said flexible means extending outwardly below the largest outside diameter of said housing for agitating fluid in such space before the largest obstruction formed by said housing is reached. 1

2. The combination of claim '1 wherein the said flexible means'is a radially projecting loop of multiple strand cable.

3. vThe combinationof claim 1 wherein the said flexible means is comprised of a plurality of relatively stiff wires in a generally radial and upward direction.

4. The combination of claim llwherein the said flexible means is a relatively stiff spring vwire forming a pair of having a plurality of flexible members 19; mounted thereon by means of appropriate retainers 21c rather thana single sleeve and single continuous cable' or wire 20 of t Each of the flexible memthe preferred embodiment. bers 190 may have a pair of loops 22c and 230 projecting upwardly and downwardly, respectively, from the retainer 210. The cylindrical portions of thisembodiment is substantially longer than the cylindrical surface 16 0f the preferred embodiment in order to accommodate the pair ofsleeves 18c.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth or to the details illustrated in the drawings,

In this embodiment, I prefer to stagger the flexible members on one of the sleeves is obtained as fingers projecting outwardly from the housing at angle to the radius thereof and having a'coil at the base of each finger with asegment of. said wire joining said coils.

5. The combination of claim 1 wherein the said flexible means is a multiple strand cable forming a pair of loops with one loop projecting radially and upwardly and the other loop projecting radially and downwardly.

References Cited in' the file of this patent UNITED STATES PATENTS 3,018,831 Gist Jan. .30, 

1. IN A TOOL FOR USE ON THE BOTTOM END OF A WELL CASING FOR CONDITIONING THE DRILLING FLUID IN THE ANNULAR SPACE BETWEEN THE WELL BORE AND THE CASING WHILE RUNNING THE CASING INTO THE WELL BORE, THE COMBINATION OF: A CYLINDRICAL HOUSING HAVING UPPER AND LOWER ENDS, THREAD MEANS ON THE SAID UPPER END OF THE HOUSING FOR CONNECTING SAID HOUSING TO THE BOTTOM END OF THE WELL CASING, DRILLABLE MEANS MOUNTED ON THE INSIDE OF THE SAID LOWER END OF THE HOUSING, THE SAID LOWER END OF THE HOUSING HAVING AN EXTERNAL CYLINDRICAL PORTION WITH AN EXTERNAL DOWNWARD FACING SHOULDER AT THE UPPER EXTREMITY OF SUCH PORTION,A SLEEVE MOUNTED ON SAID CYLINDRICAL PORTION, A PLURALITY OF 